Archive for December, 2013

For the 7th time since Folsom Dam construction was completed in 1955, the reservoir has dropped below 200,000 acre-feet in overall storage. The capacity of Folsom Lake is approximately 977,000 acre-feet. The record low occurred in the Summer Fall of 1977…and was just below 150,000 acre feet.

The Winter of 1976-77 was the driest year on record for Mammoth Mountain. We did not have snow making that year….

Earlier in the Fall we had an upper ridge that would allow California Sliders to bring wind and cold Weather to our region. It appears now that the upper long wave ridge position has moved far enough east for the PNA index to go positive. This makes for strong temperatures inversions and freezing levels in the 11,000 foot range. I expect the Freezing level to pretty much remain near or above 11,000 through the end of this week. Thus strong temperature inversions will rule with air quality degrading over time…. For the most part we are locked out of precipitation for the next two weeks and possibly through mid January. There is no MJO activity forecasted through the 6th of Jan to change the pattern. The pattern is very stable with ridging in the west…..The east will become colder with time……even though the NAO is still positive. The (AO) Arctic Oscillation is growing negative. The word is that San Francisco is about to have its driest year on record….

Although there is a weak upper low coming though the ridge this weekend bringing us a slight chance of showers….the pattern is a dry one for the state and there is nothing at this time that can change it anytime soon…..

Expect high temperatures in the low 50s in Mammoth with lows at night in the 20s and low 30s. Lower elevations of the county will be in the teens for the most part, locked under temperatures inversions. Mono Lake Fog and Pogonip will increase over time…….

Through all of this…folks are having a great time up on Mammoth Mountain as the mountain had been making snow for the past two months….

I guess I can say that that for the most part that all long range forecasts…. I mean all have gone 100% bust this Fall. So with that in mind…..I too have a prediction! I predict that for the most part, this Winter forecasts will have a 50-50 chance of being wrong as well! So what does that mean? A 50/50 chance of being wrong? It means anything a long range forecaster wants it to mean after the fact!! You will find that out at the end of this snow year which ever way it turns out! 😉 I mean that if anyone pays anyone to know what this winter is going to be, they deserves what they get!

The fact is, this is a La Nada year. There is no bias in either El Nino or La Nina! So the ability to forecast this winter is pretty slim. In this case at 50%-50% in Central California. That is why the National weather service gave Central California precipitation, equal chances. Equal chance of 100% percent of normal? No…..it means that they do not know what kind of winter this is going to be because there is little or no bias! To complicate matters further, the QBO is positive, meaning that the AO and NAO teleconnections will be mostly positive…..which by the way is what this Fall has been for the most part. When this teleconnection is positive, the flow of air out of the Arctic meridianally is much less frequent or not at all. However…Now as of last the last several days of forecast model runs………… they show the AO to become negative. That means that it is going to get very cold over the eastern half of the US. What does it mean for California? Probably nothing, as the relationship of the AO is not linier in its weather effects in California. So praying for the AO to go negative is like praying to win the lottery. Its possible, but would you really spend your last dollar trying to win it?

Now with all that said, there is still plenty of time for this winter to come back…… When that might be is not known…..The CFS is interesting for the 2nd half for January….but I would not go to the bank on that….No.

Friday Update: official word 4 to 6 inches on Mammoth Mt….. storm total with snowmaking going on all day Friday and Saturday weather permitting….

Next update Tuesday AM…..

Mammoth received some light snowfall Thursday. Although it was at the lower end of what was hoped for, about 2 to 3 inches accumulated here near the Village at Mammoth. Mammoth Mountain probably received between 3 and 5 inches. However they will update a bit later this morning.

the upper flow over the weekend will be out of the north with the upper jet over Nevada. this is a cool dry pattern. the best that can be said about it is that it will remain cold enough for snow making every night and some in the daytime today Friday as well.

By Sunday the an upper ridge builds in for the west and we become inverted again early next week. It appears that although there may be a few small systems that will modulate winds and temperatures from time to time, it will remain dry through the end of the year according to the guidance. There is some suggestion by some of the guidance that a slight shift in the pattern will occur by years end. That a weak storm or two might slip through the mean ridge position or a slight retrogression in the long wave ridge position may occur in the first week of January. However, whatever change occurs, it will most likely not be significant as there are much less ensemble members that are showing it as compared to others that are just plain dry.

For you long rangers that have the need to know what the future may hold, the Climate Forecast System (CFS) has indicated the following. (I will add as a caveat, that this experimental at best and is not to be relied upon for planning purposes).

For Mammoth Lakes (QPF)

1. From the 22nd to the 27th of December (Dry)

2. From the 27th to January 1st (Dry)

3. From Between January 1st and the 3rd. Between ( .1 and .15)

4. From between the 1st and the 5th of Jan (.3)

5. Between the 5th and the 8th (.25)

6. Between the morning of the 6th and the morning of the 11th ( . 2 to .25)

7. Between the afternoon of the 8th and the afternoon of the 13th. (.35)

8. Between Jan, 13th and the 18th (1.2)

9. Afternoon of the 18th and the afternoon of the 23rd (1.3)

10. Afternoon of the 23rd to the afternoon of Jan 28TH (.75)

11. Afternoon of the 28th of Jan thru Feb 2nd. (.7)

Total for January (QPF) between about 4 inches ( This does not include the first few days of Feb.)

Again this is experiential and not to be used for planning purposes

The average snow to water ratio is about 10:1 here in Mammoth Lakes.

Based upon the CFS guidance we might think that the chances of significant snowfall might increase about the middle of January.

In that I do not have access to the ECMWF Monthly Precip I can not compare to the CFS. However, my access to the upper height pattern at 500MB FOR 30 days and the 500MB ENSEMBLES suggests that